Means for controlling the supply of fuel to internal-combustion engines



March 12, 1946. w. D. MARCHANT 2,396,517

MEANS FOR CONTROLLING THE SUPPLY OF FUEL TO INTERNAL-COMBUSTION ENGINES Filed July e, 1945 3 Sheets-Sheet 1 W-. D. MARCH T CONTROLLING THE PPLY OF FUEL TE L-COMBUSTION ENGINES F d July 9. 1943 March 12, 1946.

mums F T0 3 Sheets-Shget 2 March 12, 1946. w. D. MARCHANT MEANS FOR CONTROLLING THE SUPPLY OF FUEL T0 INTERNAL-COMBUSTION ENGINES Filed July 9, 1943 3 Sheets-Sheet 3 m n 2 p v 2 m 9 7 H 6 fl//4/// Z. m 05 m 7 W M Z/ m Patented Mar. 12, 1946 SEATES 'FOR CONTROLLING THE SUPPLY OF FUEL T INTERNAL-COMBUSTION William Douglas Marchant, 'We hri g En land Application July :9, 1943, Serial .No. $194,050 in Great Britain July .211, 1942 4 Cla m 1. The area of therestricting orifice 2. The degree of pressure employed (positive or negative) for effectingtheiuel flow, and

3. The time factor, i. e. time during Whichfuel flow takes .place.

It is suggested that unless these three fundamental factors are in parallelism .or accordant throughout their range of operation, an accurate degree of .air and fuel meteringisnot to be expected with the ,varying speedand varyingload prevailingwith internal combustion enginesembodying. electrical .Iigm'tion.

.An examination of rthe orthodox systems :employed with internal combustion engines reveals that only two of the above :factors :are 'in parallelism, i. e. when fuel injectionis employed 1 an'cl'3 'may be in-parallel and with a carburettor system 1 and 2 maybe in parallel. While -a-i-r flow will commence the moment that the induction system is, by piston'displaoement, reducedbelow atmospheric pressurafuel flow will not commence until a relatively lower degree of depression is obtained. This is a varying factor which depends primarily upon the controlling orifice of the fuelflow,-the'throttle position and the engine speed. Compensating deviceshavebeen introduced with the object of maintaining the. air'fuel ratio Withinthe wide firing'limits, but such devices have not been entirely satisfactory and can only be considered a, crude compromise.

It is believed that thehigh percentage ofwaste in the orthodox carburettor system can beattributed chiefly toinaccurate metering or flow control and that whilst a certain quantityofiuel may have been drawn from the fuel supply by the suction stroke of a piston, a large proportion of such fuel, which toa certain degree is atomised, does not enter the combustion chamber during the said suction stroke, loutremains stagnantin'theinduction system and will. enter the cylinderin suchla mannerastobe of little -.Or no useful value; .under certain conditions thefuel having been reduced ,to astationarycondition maybe carried back by .What is known as a blow back. v#lfhese conditions vary .with engine speeds and throttleopenings.

.A lcondition similar in .effect .to blow back exists in .multircylinder internal combustion .engines having an overlapping periodjon the inlet valve pening rr/es, when the negative pressure of.a..cyli.nd r with in t ivalve openin X- ceeds the negative pressure ,of the cylinder with the .a v.e os ng. The rear pa t o t echarge is redu ed t a stat nary and sta nant condition. w rrin -.wit n in s ed an wei ht of charge. These conditions may be and are often impr ved hrsa rifi i-n p um ric e c ency. It

wou d. a pea that thelat e par o th han should be free from fuel.

It as bee oun tha f fuel i i trod c int an .a s ream .i vine a comp ra ively h hvelo i vtanex e en dea eeo atomization marin ob ained It has a. ab, e 0und thai i not advisable to permit fuel to enter the coma t on hambe ti th ri o dis l cem n is approaching its pea k. It would. therefore appear ha t a s Par 1 th harg shou d, al be free of fuel.

tziaknow tha thehieh h p ssion e hi e d re o at mizat .T h hes o n ll b .11 1 th e te .Q th p s onflis een v u .1 9 als th par p h l QWhQI over a given crank angle,;the depression ill -be approximately constant. -lt'should therefore be possible to select the correct crank angle period or correct moment ;during piston displacement creating a depression to permit fuel to flow.

Itghas beeniound-thatboth weightand quantity of a charge is. to a certain extent controlled when :a definite ratio between engine speed and restricted orifice vvor throttle "opening is maintained. While forms of. suction valves-areoften employed for attaining this object, the disadvantages ofsuCh valves are well. known.

-T,o obtain-accurate and economicmetering it is considered essential that-the fuel flow line-from point of fuel meteringtothe combustion chamber sh -h c e o ue a 'th m e iqn O each induction stroke; because of variations any fuel remaining within'this line may-notbe considered as forminga part of the following metered charge.

The invention therefore comprises a new system of controllingthe flow of fueltoan internal combustion engine which consists in theuseof means. whereby the efiect-of pressure positive,- or

negative controlling the'fuelflow is broken .down

or renclered impotent periodically, whereby fuel flow is in e u d :and o i n onl ra-predetermined period, said means being operable in timed relation to the rotation of the engine. Preferably the impotency is obtained during the suction stroke of the engine.

Where it is required that a depression is broken down, this is effected preferably through the intermediary of a valve, for example a rotary sleeve valve which is opened to the atmosphere periodically in such a manner that the fuel flows only during a period which is within theambit of the suction stroke of the engine, approximating for example an angle of 60 of the piston displacement. The valve is mechanically operated in timed relation to the rotation of the engine and becomes effective to vent the depression to atmosphere at all times other than the period during which fuel is required to flow, the venting taking place at either side of the fuel controlling orifice, in both cases the fuel flow being stopped except for a predetermined period of time during and within the angle of the displacement stroke of the piston in such a manner that a considerable increase in efliciency results over known systems of fuel control.

In order that the invention may be clearly understood, reference is directed to the accompanying drawings wherein- Figure 1 is a side elevation partly in section showing a fuel supply apparatus and control mechanism therefore in accordance with the invention;

Figure 2 is an end view of Figure l, partly in section and looking in the direction of the arrow;

Figure 3 is a sectional elevation of the upper part of Figure 1 on an enlarged scale with a slight modification of the position of conduit I5. Figure 4 is a view at right angles to Fig. 3 illustrating detail;

Figures 5 illustrates diagrammatically a furtherapplication of the invention,

Figures 6 and 7 being part views of Fig. 5 illustrating diiferent positions of the parts.

Referring to the drawings, more particularly Figs. 1 to 4, 8 indicates generally the body of the metering and mixing device hereinafter termed the apparatus, 8 being the fuel chamber thereof, ID the air inlet and II the outlet, I2 being a flange by means of which it is connected to the inlet manifold of an internal combustion engine in the usual manner. The apparatus is in communication with a valve chamber I3 housing a rotary valve or rotor I4 which controls the period at which depression is permitted to cause fuel flow through a metering orifice, air at atmospheric pressure being available at other times by way of a conduit I5 to a jet chamber I6 disposed below and forming part of the main body 8 of the apparatus. The apparatus is provided with a variably controlled orifice or jet I! through which the quantity of fuel is controlled by means of a tapered needle I8 forming part of a spindle 20 which is reciprocable in conjunction with a throttle slid 2I which controls the flow of air through the inlet I0. The slide 2I is connected by means of an arm 22 to the spindle 20 by means of a peripherally grooved collar 23 which is operatively associated with a pair of flanged screw-threaded members 24, 24, which are connected to the arm 22 in such a manner that the relative positions of the slide and the needle IB'may be adjusted. The arrangement is such that as the slide 2I is operated to open or close the air inlet to the apparatus, the spindle 20 is also raised or lowered to move the needle I8 relatively to the jet orifice I'I. The'spindle 2U slides within a sleeve 25 secured to the base of the apparatus and diametrically of the air passage therethrough, the sleeve 25 being formed longitudinally with a fuel outlet the effective area of which is controlled by the movement of the spindle 20, the fuel outlet being in the form of' a comparatively narrow slot 26 which is illustrated more particularly in Figure 4 of the drawings. The fuel is supplied to the jet I1 by means of the fuel chamber 9 and maintained, for example by means of a float, at or about a level coincident with the jet orifice. The jet I1 is surrounded by a wall 21 which forms part of the jet chamber I6 to which atmospheric air is admitted under the control of the rotary valve I4. The wall 21 is perforated at the lower end as at 28.

In order to vent the depression at all times other than the period during which fuel is required to flow, the rotary valve I4 is mechanically operated through driving connection 30 in timed relation to the engine. The valve or rotor I4 is in the form of a sleeve and is mounted within the housing I3 and controls a venting or pressure breakdown orifice 3I to the conduit I5 in communication with the jet chamber I6 enclosing the fuel orifice IT. The venting orifice 3I is in the form of a slot 32 as indicated in Figure 1 and it has been found advisable to make the opening and closing period of the slot operative over the minimum number of degrees, i. e. crank angle degrees. The rotor I4 is connected by means of a spindle 33 to a known form of governor 34 which actuates a push-rod 35 contacting one end of arm 36 pivoted to the end of the casing I3. The arm 36 is integral with one end of an operating rod 31, the other end of which is operatively connected with the slide M by means of an adjustable member 38. The operating rod 31 is held by a spring 40 which tends to keep the slide 2I in the closed position. Upon rotation of the rotor I4 the governor 34 is brought into operation to move the push-rod 35 and eventually raise the operating rod 31 to open the slide 2|. Such an operation, however, is ineffective until the usual throttle pedal or other control mechanism has been actuated to rock a pivoted lever 4I having an arm 42 which bears upon the aforesaid operating rod 31. Uponremoval of the arm by a pull on the lever 4| in the direction of the arrow indicated in Figure 1, the operating rod 3! will be permitted to move under the control of the governor 34 but not otherwise. In other words, the opening of the apparatus slide will be controlled by the engine speed which controls the governor but the closing of the said slide will be controlled by the throttle pedal which positively returns the operating rod through the medium of the lever 4I and arm 42. The operating rod, however, may be moved positively for a determined distance to a predetermined position whereby the initial acceleration is effected positively and this initial movement is conveniently effected by means of a cam 39 which bears on the operating rod and raises it a short distance as the lever M is rocked to the right in the direction of the arrow.

Figures 5, 6 and '7 illustrate an application of the invention in which a rotary valve I4 is mounted within a valve casing I3 and controls a pair of conduits 43, 44, one of which leads tothe jet chamber surrounding the jet I1 and the other to the upper part of the fuel chamber 9 or other' supply line which may be vented to atmosphere, the rotor l4 being recessed as at 45 to enable the passages 43 and 44 to be placed in communication with each other.

With such an arrangement, and assuming the conduits 43 and 44 are closed as shown in Figure 5, the continued rotation of the rotor M will place both conduits 43, 44 in communication with each other and thereby transfer the pressure existing in conduit 43 to conduit 44 and create a balancing effect upon both sides of the jet orifice, thereby bringing fuel flow to a positive halt and in a completely steady and stable condition. Having reached this condition, continued rotation of the rotor will open both conduits to atmosphere to place the fuel flow line under approximately atmospheric pressure conditions.

The fuel chamber 9 is vented at 46.

Comparative tests show the following results where the invention is applied to a standard internal combustion engine:

The use of a standard carburettor limits the fuel available to petrol whereas with apparatus in accordance with the invention heavier fuels such as kerosene can be used in addition to petrol and will give approximately the same power output for the same consumption of fuel.

For convenience the present invention has been described with the main components of the apparatus assembled as a unit, but it is to be understood that each of the component parts could be separated, for example the rotor could be placed at any convenient position adjacent the accessory driving shaft by which it may be driven; the fuel chamber may be at any convenient part of a motor vehicle and the mixing and metering apparatus may be directly attached at any point of the induction system or in communication therewith. Furthermore, the breakdown may be effected at either side of the fuel orifice-breaking down on the entry side would permit fuel flowbreaking down on exit side would prevent fuel fiow. Breaking down at the entry side would be effected, for example, at the fuel chamber by placing the latter under a pressure equal to the exit side of the jet orifice.

What I claim and desire to secure by Letters Patent is:

1. Apparatus for controlling the fiowof fuel to an internal combustion engine comprising an orifice for the supply of fuel to an air inlet to the engine under the action of engine suction, a jet chamber in communication with said air inlet through said fuel orifice, and means operable in timed relation to the rotation of the engine to vent said jet chamber for a predetermined period within the ambit of the suction stroke of the engine without affecting the rate of air flow to said engine.

2. Apparatus for controlling the flow of fuel to an internal combustion engine comprising an orifice for the supply of fuel to an air inlet to the engine under the action of engine suction, a jet chamber in communication with said air inlet through said fuel orifice, and a valve operable in timed relation to the rotation of the engine to vent said jet chamber for a predetermined period within the ambit of the suction stroke of the engine without affecting the rate of air fiow to said engine.

3. Apparatus for controlling the flow of fuel to an internal combustion engine comprising an orifice for the supply of fuel to an air inlet to the engine under the action of engine suction, a jet for the supply of fuel to said air inlet through said orifice, and means operable in timed relation to the rotation of the engine to effect a subatmospheric equalization of the air pressure acting on the fuel entering said jet with the air pressure acting on the outlet of said jet for a predetermined period within the ambit of the suction stroke of the engine.

4. Apparatus for controlling the fiow of fuel to an internal combustion engine comprising an orifice for the supply of fuel to an air inlet to the engine under the action of engine suction, a jet chamber in communication with said air inlet through said fuel orifice, a fuel chamber communicating with a jet in said jet chamber and having an overlying vapor space, and means operable in timed relation to the rotation of the engine to effect intercommunication between the vapor space of said fuel chamber and said jet chamber for a predetermined period within the ambit of the suction stroke of the engine.

WILLIAM DOUGLAS MARCHANT. 

